The unit, once mounted, measuring approximately 08 cm. It is built using pre rooms - cut from two sheets of aluminum. The rooms are very well done and attach it between using tabs and holes. These fall perfectly face to face and it is therefore the really good thing about this "model". By cons, we must be very clever with his fingers and have the proper tools. Personally, I have not finished because it's really too fussy for me (43 years). I do not pretend to be a modeling expert, but I have installed a lot of models and I've always come to the end. But for this device, it was an ordeal, so no fun to build it. Let me explain: first, when you have mounted a portion of the device, if you are not completely satisfied, are not retouch. Indeed, if you unfold and fold the piece twice, aluminum breaks. On the other hand, and that's really what got me the most "angry" is the construction of the reactors. I can admit that I'm clumsy, but admit that build cylindrical reactors 5 mm diameters, starting from a sheet of aluminum, not that easy to fold, it notes of an expert in this type of model . Anyway, I still put two stars because I think that there is a blunder by me and I want to stay objective. But if I had to rate this model due to my personal experience, I would (unfortunately this is not possible) no stars ..... 15 euros in the trash (counting shipping). For cons, I was delivered very quickly .... In short for those who want to indulge, try may be a simpler model without cylindrical parts, for starters.